We propose to determine if FDG positron emission tomography (PET) with or without parametric imaging is more accurate than rapid sequence contrast enhanced spiral CT, which is the standard clinical non-invasive method in the detection of colorectal carcinoma metastatic to the liver. Accuracy of PET and CT performed preoperatively will be determined by direct gross and histologic examination of the liver removed from patients who undergo partial hepatic resection as therapy for metastatic colorectal carcinoma.